Feiedeich lehnee



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P. LBHNER.

PROCESS OI MAKING ARTIFICIAL SILK.

Patented May 5, 18961.

Nirnn STATES y FRIEDRICH LEI-INEE, OF

Fnicn.,

i ATENT zURIoI-I, SWITZERLAND."

SPECIFICATION forming part of Letters '.Patent No. 559,392, dated May 5, 1896. Application filed April 16,1895. Serial'No. 545,930. (No specimens.) Patented in Germany September 16, 1890,1Tol 58,508,l

in Italy September 80, '1890,No. 27,948; in Austria-Hungary April June 22,1891,No. 3,740, and in England J'uly 11, 1891,1To. 11,881.

To all whom t may concern.-

Be it known that I, FRIEDRICH LEHNER, a citizen of Germany, residing at Zurich, Switzerland, have invented certain new and useful Improvements in Processes of Making Artificial Silk, (patented in Germany, No. 58,508, dated September 16, 1890 5 in Great Britain, No. 11,881, dated July 11, 1891; in Italy, No. 27,943, dated September 30, 1890; in Austria- Hugary, No. 54,002 and No. 9,475, dated April 29, 1891, and in Switzerland, No. 3,740, dated June 22, 1891;) and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to the art of manufacturing artificial silk, and its object is the production of a thread which has all the glossy appearance and other properties of natural silk and which is incombustible or difiicult of combustion.

For this purpose my invention consists in the method and other features herein after set 'The result of this neutralization is that the silk substance (a mixture of fibroin and sericin) is slowly precipitated or thrown out of the solution in the form of iine threads having a pale reddish color. The pure substance thus obtained is thoroughly washed with water, the water expressed by light pressure, and the said substance is then dissolved in concentrated acetic acid in the proportion of one to five. This solution I term solution A.

The second solution, which I term solution B, is obtained as follows: Cellulose, silk pa- 29, 1891,11'0. 54,062 and No. 9,475,I in Switzerland per, cotton or spinning wastes are macerated for substantially a quarter of an hour with a solution of copper or a copper salt in ammonia, the solution is expressed, andthe residue thoroughly washed with water and nitrated in the ordinary way. The nitrocellulose so obtained is now dissolved in a Ymixture of wood-spirit (methyl alcohol) or ether and ethyl sulfuric acid, (G2II5.I^ISO4,) said mixture being preferably in the proportion of three parts of the former to one part of the latter. While I have claimed the use of wood-spirit specically, it is to be understood from the above description that I consider ether as an equivalent of the wood-spirit so far as its use in my process is concerned. The ethyl sulfuric acid used in this process may be obtained by mixing two parts of strong alcohol with one part sulfuric acid of ,600 Baume, and gradually heated to 100o centigrade. The nitrocellulose is dissolved in the mixture of wood-spirit or ether and ethyl sulfuric acid in the proportion of eight parts of the former to one hundred parts of the latter and maintained at a heat of 80o centigrade for about one hour. A denitration of the dissolved nitrocellulose takes place under these conditions, nitroethene being evolved and escaping. The two solutions A and B are united, preferably, in such a way that iive parts of nitrocellulose are combined with one part silk substance, (silk fibroin.) From the mixture so obtained theV thread of artificial silk is formed by simply allowing said mixture to pass through a fine opening into a congealing or solidifying bath, preferably oil of turpentine, petroleum, benzin, benzol, liquid hydrocarbons, and other liquids free from oxygen.

An apparatus for carrying out this process is illustrated in the accompanying drawing, which represents the same in sectional elevation.

In the drawing, a represents the tank for containing the mixture of the solutions A and B. h represents the vessel containing the congealing or solidifying liquid. A pipe c, pro vided with a suitable cock or other regulating device, communicates with the tank c, .and

is provided with an outlet or small orifice CZ at or near the bottom of the vessel Zi, through which the liquid mixture from a passes into the liquid contained in the vessel b, below the level of the said liquid. This orifice dislocated below the level of the liquid in the tank '66, so that it will be forced into the congealing liquid under a certain head or pressure. The liquid from a, as it passes through the liquid in the vessel Z2, is congcaled or solidified and formed into a thread e, which is drawn forth from the con gealin g-bath and spun and wound by suitable machinery. It is not necessary to go any further into the description of the apparatus for the method of forming the thread in this application, as the same has been claimed in my application, Serial No. 401,014, iiled July 25, 1891, and forms no part of the present invention. The thread so formed is then preferably further treated under my invention to further denitrate the pyroxylin and to remove the oil of turpentine or petroleum adhering thereto. For this purpose the thread is heated with water to about 80o centigrade for about one hour. Under this action a further denitration of the pyroxylin takes place owing to the decomposition of the free ethyl sulfuric acid present in the thread. Thereupon the thread is thoroughly rinsed with water and laid into a solution containing about ten parts soluble glass for several days, whereby the sulfuric acid still adhering is neutralized, the silicic acid being hereby separated and filling up the pores of the thread, whereby the same is made still more incombustible; or the sulfuric acid may be neutralized by laying the thread for about twenty-four hours into a solution of ammonia of the specific gravity of 0.975 before washing the same with water. The thread is thereupon dried in the air.

lVhat I claim, and desire to secure by Letters Patent, is-` 1. rlhe process which consists in mixing a solution of silk substance with a solution of nitrocellulose7 and drawing forth the thread from such mixture.

2. The process which consists in mixing a solution of silk substance with a solution of nitrocellulose, and causing the said mixture to pass through a congealin g bath or solution to form a thread.

3. The process which consists in mixing a solution of silk substance with a solution of nitrocellulose, and causing the said mixture to pass through a con gealing bath or solution containing no oxygen, to form a thread.

l. The process which consists in mixing a solution of silk substance with a solution of nitrocellulose, and causing the said mixture to pass through a congealing bath or solution of a hydrocarbon or hydrocarbons, to form a thread.

5. The process which consists in digesting sillcwaste with caustic alkali and a solution of copper or a copper salt-in ammonia, then precipitating the silk substance from said solution and dissolving the said precipitate in concentrated acetic acid.

G. The process which consists in maeerating cellulose, silk paper, cotton or other substance containing cellulose, with a solution of a copper salt in ammonia and then nitrating the saine, and iinally partially denitrating the resulting nitrocellulose.

7. The process which consists in macerating cellulose, silk paper, cotton or other substance containing cellulose with a solution oa copper salt in ammonia, then nitrating the same, and then dissolving the resulting nitrocellulose in a mixture of wood-spirits or ether and ethyl sulfuric acid to partially dcnitrate the same.

8. The process which consists of the following steps: iirst, preparing two solutions of, firstly, silk-waste digested with caustic alkali or a solution of copper or a copper salt in ammonia, precipitated from such solution and iinally dissolved in concentrated acetic acid, secondly, a substance containing cellulose macerated with a solution of copper or a copper salt in ammonia and nitrated and then partially denitrated, mixing the two solutions thus formed, and drawing the thread forth from said solutions.

9. The process which consists of the following steps: iirst, preparing two solutions of, firstly, silk-waste digested with caustic alkali or a solution of copper or a copper salt in ammonia, precipitated from such solution and iinally dissolved in concentrated acetic acid, secondly, a substance containing cellu lose macerated with a solution of copper or a copper salt in ammonia and nitrated and then partially denitrated, mixing the two solutions thus formed, and causing the said mixture to pass through a congealing solution or bath whereby a thread is formed.

10. The process which consists in adding a solution of silk substance to a solution of partially denitrated nitrocellulose, passing the thread through a solution containing oil of turpentine or other hydrocarbon, and rendering the thread incoinbustible by heating with water and rinsing.

11. The process which consists in treating a solution of cellulose with a solution of a copper salt in ammonia, then nitrating the same, then preparing ethyl sulfuric acid by dissolving two parts strong alcohol in one part sulfuric acid and gradually heating to 1000 centigrade, then adding the ethyl sulfuric acid to woodspirits, then dissolving the nitrocellulose in the bath so obtained to partially denitrate the same, then adding this solution of nitro cellulose to a solution of silk substance, then drawing forth the thread and finally renderA ing the thread incombustible by neutralizing the sulfuric acid 'still adhering to the same.

12. In a thread of artificial silk, the com IOO IIO

bination,ofnitroeellulosewithsilksubstenoe, tially-denitrated cellulose and silicio acid,

substantially as set foith. substantially as set forth. io 13. In a thread of artificial silk, the com- In testimony whereof I afiix my signature hinzttion, of a silk substance, With partiallyin presence of two Witnesses. 5 clenitrated nitrocellulose, substantially as set FRIEDRICH LEHNER.

forth. Y IVitiiesses 14. A thread of artificiel silk consisting of I-I. LABHART,

a silk substance, in combination with pai EMILIE MAJORES. 

